How to Grow Cosmos in a Container

Cosmos are annual plants with dainty stems and colorful, long-lasting blooms available in an assortment of cheerful colors. These include various shades of yellow, red, pink, purple and white. The plants need little attention to do well and don't develop an extensive or deep root system, making them a good choice for container planting. Cosmos thrive in well-drained soil and direct sunlight. They don't require large amounts of nutrients and tend to develop a leggy appearance when grown in fertile soil. Cosmos seeds can be sown directly into the chosen container after frost danger passes in spring.

6-inch growing container
Lightweight potting mix
Scissors
Balanced water-soluble fertilizer
Pruning shears

Instructions

- 1
  Choose a container that is at least 6 inches wide and has one or more drainage holes in the bottom.
- 2
  Fill the container three-fourths of the way with lightweight potting mix.
- 3
  Sow the cosmos seeds approximately 1/4 inch deep and water until the potting mix feels moderately moist.
- 4
  Place the container in full sun exposure and keep the soil lightly moist until the seedlings emerge. Continue to water as necessary to keep the top 1/2 inch of soil lightly moist after all of the seedlings sprout.
- 5
  Thin the seedlings when they are 4 inches tall, leaving only four to eight of the sturdiest plants in place, depending on the size of the container. Snip the seedlings off level with the growing mix instead of pulling them to prevent damage to the remaining cosmos plants.
- 6
  Feed each week with balanced water-soluble fertilizer applied at one-fourth the rate suggested on the fertilizer directions.
- 7
  Clip off flowers as they fade to prolong the blooming cycle. Trim off dead leaves to maintain a tidy appearance.

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